lubridate

!

Tokyo.R#50 2015-09-05 @kashitan

lubridate

#Tsurami

lubridate

Date

!

POSIXct(POSIX calendar time) POSIXlt(POSIX local time)

Date 197011

>#1970110>as.Date("1970-01-01")%>%+as.integer()[1]0>>#2015953>as.Date("2015-09-05")+3[1]"2015-09-08">>#(difftime)>(as.Date("2015-09-05")-as.Date("2015-09-01"))%>%+as.integer()[1]4

POSIXct 197011000

>#1970110000>as.POSIXct("1970-01-0100:00:00",tz="UTC")%>%+as.integer()[1]0>>#2015953>as.POSIXct("2015-09-0512:34:56",tz="Japan")+3*60*60[1]"2015-09-0515:34:56JST"

POSIXlt

>todayunclass(today)$sec[1]56$min[1]34$hour[1]12...>>#>today$hour[1]12

#Tsurami

#Tsurami

format

POSIXlt

format yyyy-mm-dd, yyyy/mm/ddformat

>as.Date("20150905")charToDate(x):> >as.Date("20150905",format="%Y%m%d")[1]"2015-09-05"> >as.POSIXlt("20150905123456",format="%Y%m%d%H%M%S")[1]"2015-09-0512:34:56JST"

%m%M

POSIXlt $year, $mon

>today#$year1900>today$year[1]115>>#$mon0-11>today$mon[1]8>>as.POSIXlt("2016-01-01")$mon[1]0

1900

1

format(ry

>#30>dd+months(1)[1]"2015-02-01""2015-03-02">d+days(30)[1]"2015-01-31""2015-03-04">>#>dd[1]"2015-09-01""2015-09-02"

Whats lubridate? Date, POSIXt

Hadley

Whats lubridate? Date

P.32 Hadley Wickham, an author of several popular R packages, has often made use of this data set in illustrating data manipulation in R.

#Tsurami

format

POSIXlt

format ymd(), mdy(),dmy()format

>library(lubridate)!>ymd("2015-09-05")[1]"2015-09-05UTC">ymd("20150905")[1]"2015-09-05UTC"!>mdy("Sep-05-2015",locale="C")[1]"2015-09-05UTC">>dmy("05/09/15")[1]"2015-09-05UTC"

format ymd(), mdy(),dmy()format

>library(lubridate)!>ymd("2015-09-05")[1]"2015-09-05UTC">ymd("20150905")[1]"2015-09-05UTC"!>mdy("Sep-05-2015",locale="C")[1]"2015-09-05UTC">>dmy("05/09/15")[1]"2015-09-05UTC"

locale=C

format ymd_hms(), mdy_hms()POSIXt

>ymd_hms("20150905123456")[1]"2015-09-0512:34:56UTC"!>options(digits.secs=3)>ymd_hms("2015-09-0512:34:56.789")[1]"2015-09-0512:34:56.789UTC"!>mdy_hms("Sep-05-201512:34:56.789",locale="C")[1]"2015-09-0512:34:56.789UTC"

format

>#creatingheterogeneousdateobject>hetero_date#parsingthecharacterdateobjectandconverttovaliddate>ymd(hetero_date,locale="C")[1]"2013-08-24UTC""2013-08-18UTC""2013-08-23UTC"

POSIXlt year(),month()

>#>ctct[1]"2015-09-0501:20:26.254JST"!>#>year(ct)[1]2015!>#(label=TRUE)>month(ct)[1]9

POSIXlt year(),month()

>#(day or mday)>day(ct)[1]5>#>wday(ct)[1]7>#>week(ct)[1]36>#>yday(ct)[1]248

POSIXlt year(),month()

>#>hour(ct)[1]1>#>minute(ct)[1]20>#>second(ct)[1]26.25421

year(),month()

>dd[1]"2015-01-01UTC""2015-02-02UTC!>#9>month(d)d[1]"2015-09-01UTC""2015-09-02UTC!>#2016>year(d)d[1]"2016-09-01UTC""2016-09-02UTC"

? with_tz()

!

leap_year()

>#>with_tz(now(),"America/New_York")[1]"2015-09-0413:04:21.272EDT

>#>dd[1]"2015-01-01UTC""2016-01-01UTC""2017-01-01UTC"!>leap_year(d)[1]FALSETRUEFALSE

lubridate!!